Attenuating apparatus



All@ 9, 1960 F. H. BAILIFF' 2,948,021

ATTENUATING APPARATUS Filed March 28, 1957 30 INVENTOR.

FRED H. BAILIFF United States Patent O ATTENUATING APPARATUS Fred H. Bailiif, South Charleston, W. Va., assignor to Union Carbide Corporation, a corporation of New York Filed Mar. 28, 1957, Ser. No. 649,152

3 Claims. (Cl. 19-65) This invention relates to at-tenuating apparatus for converting a tow or sliver into random length bers and dspersing the separated bers in an air stream generated by a rapidly revolving beater roll.

In the manufacture of ber glass preforms or mats for reinforced plastic laminates, it is usual to build up a preform or mat of chopped strands cut to approximately two inches in length from glass roving. These strands are deposited by air currents onto a perforated screen, the -air being exhausted through the screen. l

It has been proposed to supply thermoplastic binder bers into the plenum chamber to be carried by the air currents onto the perforated screen, usually along vn'th the glass strands.

'Ilhe main object of the present invention is to provide apparatus for supplying the thermoplastic bers for thisy rocess.

p According to the present invention the attenuating apparatus comprises a drafting head having drafting rolls, and a beater roll which takes the individual thermoplastic fibers as they emerge from the drafting head and projects them into the air stream in the plenum chamber for intimate mixing with glass bers. The apparatus is also useful for recovering `glass bers from imperfect preforms Vand mats by passing the preforms or mats through the machine in the same manner as tow or sliver.

The drafting head or breaking down section of the ber feeding device has three sets of rolls and consists of two drafting Zones. The bottom roll of each pair is positively driven through suitable gearing from a common variable `speed source. Both the top and bottom rolls are tinted so that they intermesh and the top rolls are held down by suspended weights. The ratch between the nip of the rolls can be varied, and the draft in each zone can be varied.

Following the drafting head is a beater roll tted with flexible fingers, preferably rubber bands, which disintegrate the attenuated sliver or broken tow into individual fibers. and has its axis in the plane of the nip of the rolls of the drafting head, and parallel to the last set of drafting rolls. It is positioned so that the rubber ngers can reach into or at least whip close to the nip of the rolls. The peripheral surface is tted with rubber bands which are held in holes drilled in the surface. These holes are in staggered rows around the circumference.

A sliver or tow is fed into the drafting head and subjected to two drawings before it emerges from the nip of the third set of rolls. Here the drafted sliver or broken tow is separated into individual bers by the rapidly rotating beater roll which is equipped with the rubber ngers.

The beater roll is rotated at a high speed of from 2000 to 8000 r.p.m. and the rubber fingers pick off the bers as they emerge from the nip of the last set of draw rolls. 'I'he fingers of the beater roll project or throw the binder bers into the plenum chamber where they are This roll is, for example, 21/2 inches in diameter i 2,948,021 Patented Aug. 9, 1960.

carried by air currents into the perforated screen, along with the glass strands.

In the drawings:

Fig. l is a vertical section through a drafting head and beater roll according tothe preferred embodiment of the present invention; and

Fig. 2 is a horizontal section taken along the tline 2-2 of Fig. 1.

As shown in the drawing the drafting head comprises a box-like frame or casing having a base 10 and a pivoted top portion 12 closed by an eyebolt 14 pivoted on the base 10 and spring pressed by a handwheel 15. Journaled in the base frame 10 are the lower rolls 17, 19, and 21 of pairs of fluted drafting rolls, the coacting nipper rolls 16, 18, and 20 of which #are journaled in sliding bearings in the pivoted top frame 12. These sliding bearings are individually spring pressed and adjustable by handwheels 22.

The upper rolls are provided with a clearer board 24 pivoted at 25 and held in contact with its rolls by its own weight. The lower rolls are provided with a clearer board 26 pivoted on la rod 27, each end of which rides in a slot 28 in the base 10 having a retaining notch at its upper end. The front end of the lower clearer board is supported by spring pressed rods 29 which4 enter retaining holes in the base.

This arrangement permits the bottom clearer board 26 to be dropped for cleaning by grasping the angle extensions of the rods 29 and pulling the rods out of their retaining holes, and lowering the rods 27 along the slots 28. After cleaning, the `clearer board 26 is raised to bring the rods 27 into the notches in the tops of slots 28, and the front rods 29 snap into their retaining holes in the base 10.

Iournaled in the base frame 10 and forming the pivot for the top portion 12 is a beater shaft 30, on which is keyed a beater roll 32 provided with flexible elastic ngers or laments 34. The ngers 34 are preferably rubber bands, but may be laments of crepe rubber or synthetic elastic material. The lingers 34 are preferably staggered in rows of bunches mounted in drillings in the periphery of the roll 32.

The tow or sliver 36 in its course through the drafting head passes between the coacting rolls of the sets, the lower rolls of which are driven at increased speed by conventional gearing not shown. The upper'rolls of the sets are driven bythe mutual engagement with the flutes of the lower rolls. Rolls 16 and 17 engage the tow or sliver 36 rst, -andthe speed of these rolls is preset to give the desired percentage addition of thermoplastic ber to the preform or mat.

Rolls 18 vand 19 lare driven at a faster rate so that in passage thereto bers of the tow or sliver 36 are broken ordrafted as at 38 because of the tensile stress produced. Similarly in passage of the broken tow or sliver 38 therefrom to the rolls 20 and 21 the tensile stress is again increased, resulting in breaking or drafting those of the bers of the broken tow or sliver 40 which were not broken or drafted in the rst drafting stage.

As 4the band of broken bers emerges from the rolls 20 and 21 `it is contacted by the beater ngers 34. 'Ihe beater roll 32 is positioned so that the rubber ngers can reach into or at least Whip close to the nip of the final drafting rolls 20 and 21 and disintegrate the broken tow y40 into individual bers 42.

What is claimed is:

1. Attenuating apparatus comprising a drafting head in which is journaled a series of rolls through which a sliver passes, and a beater roll provided with thin narrow elastic laments and journaled in position so that the ends of said laments whip close to the nip of the nal usually 3 drafting rolls to disintegrate the attenuated sliver into individual bers.

2. Attenuatng apparatus as claimed in claim l, in which said elastic filaments are constructed of rubber bands staggered in rows of drillings in the periphery of said beater roll.

3. Attenuating apparatus comprising a drafting head in which is journaled a series of rolls through which a sliver passes, and a beater roll provided with bunches of thin, narrow elastic filaments in staggered relation on the periphery of said beater roll, said beater roll being 4 journaled in position so that the ends of said laments whip close to the nip of the nal drafting rolls to disintegrate the attenuated sliver into individual fibers.

References Cited in the ile of this patent UNITED STATES PATENTS 1,452,352 Balls Apr. 17, 1923 2,327,087 Austin Aug. 17, 1943 FOREIGN PATENTS 68,026 Holland June 15, 1951 

